Bisphenol A (BPA) is one of the highest production chemicals in the world. It is used in polycarbonate beverage containers, food packaging, linings of food cans, and sealants for teeth. Public health concerns have been raised about BPA because recent studies demonstrate: 1) that it is an endocrine disruptor that acts as an estrogen at low doses;2) that it leaches from consumer products into food and water;3) and that human exposure is nearly ubiquitous. Animal studies suggest that BPA alters sexual and reproductive development, including sexually-dimorphic alterations in brain structure and behavior;increased weight gain;and earlier puberty. Because of these health concerns, several countries and U.S. states are considering legislation to ban BPA. However, almost no studies to date have examined the health effects of BPA in humans. This proposal seeks to address this data gap by examining the health effects of developmental BPA exposure in a cohort of children living in California. The CHAMACOS Study is a longitudinal birth cohort study that has followed ~500 low-income children living in a predominantly Mexican-American, farmworker community from before birth to age 9. Children's growth, health, neurodevelopment, and behavior have been assessed at birth and age 6 months, 1, 2, 3 1/2, 5, and 7 years of age and urine and/or blood samples were collected at each time point. In this rich dataset, the intent is to examine the association of BPA exposure in utero and in childhood with child growth and development. The specific aims are: 1) to measure BPA concentrations in urine collected from ~400 mothers during pregnancy and from their children at 6 months, 5 years, and 9 years of age. All samples, except those at age 9, have already been collected: 2) to determine whether maternal BPA concentrations are associated with maternal (TSH, T3, T4) and child (TSH) thyroid hormone levels. 3) to determine whether maternal and childhood BPA concentrations are associated with cognitive functioning and behavior at age 5 years.;4) To determine whether maternal and childhood BPA exposure is associated with body mass at age 5 or age 9 years;and 5) To determine whether maternal and childhood BPA exposure is associated with metabolic syndrome at age 9 years. Data has already been collected on thyroid levels in mother and child and neurobehavioral development and body mass at age 5 years. Metabolic syndrome diagnosis will be determined from new data gathered at age 9 (blood pressure, waist circumference, lipids and glucose in fasting blood). This project is uniquely suited for this Grand Opportunities RFA because it uses an extant dataset and banked samples, it focuses on developmental exposures, and it can be begun immediately and completed in 2 years. This is a potentially high-impact project that can provide immediate answers about the human health effects of BPA exposure to legislators and policy makers and lays the groundwork for future investigations. PUBLIC HEALTH RELEVANCE: The proposed research will provide some of the first data on the human health effects of BPA exposure and address key data gaps identified by advisory and regulatory bodies. By relying mainly on existing data and banked samples, we will accelerate the science by completing the research in just two years. In addition, measurement of BPA in this cohort will lay the foundation for future examination of multiple other outcomes, such as asthma (including spirometry), immune function (Th1 and Th2 cytokines), and pubertal onset, in this rich and unique dataset.